People in England are being advised to test for Covid before going to crowded places.
The government also advises that people test before spending time with those at greater risk from coronavirus.
When should people in England be taking tests?
Official guidance for England has been updated to recommend that people take free NHS lateral flow tests (LFTs) before going to high-risk settings this winter.
This includes spending time in busy places such as shopping centres, or where there is limited fresh air, or when visiting vulnerable people.
People are also reminded to follow any specific testing guidance for places such as health and social care settings, schools and prisons.
What's the advice in the rest of the UK?
Everyone in Scotland is encouraged to test twice a week. First Minister Nicola Sturgeon has also asked people to make an "extra effort" with testing over the festive period. She said people should test themselves before they socialise or go shopping in busy areas.
People in Wales are encouraged to take LFTs twice a week if they are:
- not fully vaccinated
- classed as vulnerable
- in close contact with a vulnerable person
- spending time in a higher risk environment
In Northern Ireland, regular LFTs are recommended for anyone over the age of 12 who:
- has a large number of close contacts
- spends time in a crowd or a busy public place
- socialises in a group
- has contact with someone who is clinically vulnerable
- can't get the vaccine due to age or a health condition
How do I get a lateral flow test?
Across the UK, you may be offered a test through your employer or school.
Anyone who tests at home is asked to report their result online or by calling 119.
How do the tests work?
Lateral flow tests and polymerase chain reaction (PCR) tests do different things:
- LFTs pick up the most infectious people by detecting material from the surface proteins of the virus
- PCRs detect genetic material of the virus which can be present in the body for several weeks after somebody is actually capable of passing it on
Both tests involve swabbing your nose and/or throat.
But LFTs can be done at home, and show results in 20-30 minutes. PCR test swabs must be sent to a lab for analysis, with results provided in 24-48 hours.
What if I test positive?
Under the current system, if you get a positive LFT result, you have a legal obligation to self-isolate immediately, as does any adult in your household who is not fully vaccinated.
You must get a PCR test as soon as possible to confirm the result.
This can be booked online, or by calling 119.
If you receive a negative follow-up PCR test result (if taken within two days of the positive LFT), you can stop self-isolating.
However, you must continue to self-isolate if the PCR result is positive, you choose not to take a follow-up PCR or the test was taken more than two days after the positive LFT.
How reliable are lateral flow tests?
When lateral flow tests (LFTs) were first trialled in Liverpool in 2020, they were criticised for being less reliable than PCR tests.
But when UCL researchers used a new formula to calculate the rapid tests' accuracy, they found LFTs were:
- More than 80% effective at detecting any level of Covid-19 infection
- Likely to be more than 90% effective at detecting who is most infectious
This is much higher than previously thought.
What if I have Covid symptoms?
Anyone across the UK with Covid symptoms - a new continuous cough, high temperature, or change in sense of taste or smell - has a legal obligation to self-isolate immediately.
You must take a PCR test as soon as possible. You can order a test kit to be sent to your home or book an appointment at a walk-in or drive-through test site.
You must not leave home until you get your test results, except to post a test kit or for a PCR test appointment.
What about tests for travelling?
You may need to take a Covid test before travelling to your destination, or on your return to the UK.
You cannot use NHS-provided LFTs or PCRs for this purpose, and must buy tests from a private provider.